This project, a specialized Cancer Research Center within the Department of Radiation Therapy, supports a variety of basic studies designed to clarify certain aspects of cellular and tissue radiation biology. Individual projects within this Cancer Research Center are periodically reviewed and evaluated as to scientific progress. The Center supports research in bone marrow stem cell kinetics, cellular radiation biology, drug/x-ray interaction in mammalian cells in culture, studies into the molecular organization of mammalian cell DNA, the immunology and immunotherapy of an experimental mouse ovarian tumor, and various aspects of radiological physics as they relate to the improvement of dose distribution within a treatment volume during a course of radiation therapy. BIBLIOGRAPHIC REFERENCES: Hellman, S.: Cell kinetics, models and cancer treatment - some principles for the radiation oncologist. Radiology 114: 219-223, 1975. Chaffey, J.T., Rosenthal, D.S., Pinkus, G. and Hellman, S.: Advanced lymphosarcoma treated by total body irradiation. Brit. J. Cancer. Suppl. II. 31: 441-449, 1975.